Preheat the oven to 200°C.
Heat the olive oil in a large, heavy-based saucepan over a medium heat. Sweat the carrot and courgette for 5-6 minutes, stirring occasionally. Remove from the heat and transfer to a large mixing bowl. Add the cabbage, crab meat, celery, chopped chives and seasoning. Stir well to combine.
Lay the sheets of pastry on a flat surface and fill generously with the filling. Brush the edges with the beaten egg and bring up and around the filling to form a ball of filled pastry, sealing well. Carefully turn upside down and sit with the seam-side down on a line baking tray.
Bake for 20-25 minutes until the pastry is golden brown in colour. Remove and arrange in serving dishes, garnished with the chive stalks.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.